UPDATED: 17.35pm AIRLINE baggage restrictions have been eased after the terror threat to Britain was downgraded.

The change means that passengers can take on board one small cabin bag, but liquids remain banned.

Stansted and Luton airports introduced the new guidelines at 12pm today.

At 3pm, it was implemented at Heathrow Terminal 1 for domestic departures and for all domestic flights departing Gatwick.

Airport bosses BAA said the new rules will be phased in for international flights tomorrow morning.

The news will come as a huge relief to passengers who have had to endure chaos since the alleged plot to blow transtalantic planes was foiled five days ago.

Overnight, the terrorism alert status was reduced from "critical" to "severe" by the Joint Terrorist Analysis Centre, which means an attack is "highly likely" - but not "imminent".

Across Heathrow 68 flights were cancelled today, but fewer cancellations were anticipated tomorrow.

There is an average delay on arrivals of about 50 minutes.

At Gatwick, "a number of delays and cancellations were inevitable" and passengers were advised to check with their airline before travelling to the airport.

British Airways has cancelled all 26 of its domestic flights from the airport, except to Jersey, and easyJet scrapped seven.

At Stansted, 15 departing flights were cancelled.

Ryanair, the largest carrier operating out of Stansted, attacked BAA for forcing it to cancel seven flights today.

"No other UK airport has asked or required Ryanair to cancel any flights to accommodate these additional security measures," the compnay said in a statement.

"However, we have advised BAA Stansted that the majority of our flight schedule will operate from today onwards, as it is not unreasonable to expect that BAA Stansted should meet its security obligations to all passengers five days after the events of the Thursday 10th August."

Early this morning the Department for Transport issued the revised rules on cabin baggage.

Eased airport security measures:

  • Each passenger is permitted to carry one item of cabin baggage through the airport security search point. The dimensions of this item must not exceed: a maximum length of 45 cm, width of 35 cm and depth of 16 cm (17.7"13.7"6.2" approx) (including wheels, handles, side pockets etc.).This is relatively similar in size to a small laptop bag.
  • The bag must NOT contain:

- Any liquids, cosmetics or toiletries, including gels, pastes, lotions, liquid/solid mixtures, perfumes and the contents of pressurised containers - these must be checked in as hold baggage.- Cigarette lighters are NOT permitted in hold baggage or through the security search. These may be purchased airside.

  • The bag CAN include:

- Electronic equipment including mobile phones, digital cameras and MP3 players (such as iPods).- Prescription medicines in liquid form, eg diabetic kit.- Baby milk and liquid baby food (the contents of each bottle MUST be tasted by the accompanying passenger). - Laptops must be removed from the bag for x-ray.

  • All remaining items in pockets should be placed in the clear plastic bag provided, eg car keys and fobs, cash, solid food, books, newspapers, cigarettes and tobacco.
  • Pushchairs and walking aids are permitted but must be x-ray screened. All wheelchairs will be subject to search. Please note: You may be subject to a hand search by the security team and required to remove footwear to be x-ray screened.
  • Once in the departure lounge passengers may purchase any item in any store and take it onto the aircraft as normal unless you are travelling to the USA.

DfT said it would work closely with operators to introduce the new arrangements, seeking to keep disruption to passengers "to a minimum". The new measures would be kept under review.

If passengers have any questions on their travel arrangements or security in place at airports, they should contact the airport or their airline.

Last night a British Airways flight from London to New York was forced to turn back to Heathrow mid-flight after a mobile phone rang.

The ringing reportedly sparked a major scare when none of the passengers would claim ownership of the phone.

The aircraft was one and half hours into its transatlantic flight.